Conventionally, when forming circular stitches with a sewing machine, a circular stitcher having a needle provided on it is attached to the sewing machine. The needle secures the workpiece cloth at a pivotal point laterally spaced from the sewing needle drop point. Then, the workpiece cloth is rotated about the needle by the feed dog to form circular stitches in coordination with the vertical movement of the needle bar having a sewing needle attached to it. One example of such circular stitcher is disclosed, for example, in patent publication JP 2008-253725 A.
The circular stitcher disclosed in JP 2008-253725 A is provided with a main base attachable to the upper surface of a sewing machine bed or a needle plate, a pin support (movable base) provided laterally movably on the main base, and a pin supported by a cloth slider of the movable base. The pin support extends laterally and has an upwardly oriented needle at its right end relatively closer to the sewing needle drop point. The pin support is locked in place at its left end by a lock element provided on the underside of the cloth slider.
Since the circular stitcher rotatably supports the workpiece cloth on its upper surface, it is preferable to reduce the clearance between the circular stitcher and the needle plate as much as possible. This is because increased difference in height between the upper surface of elements such as the support pin and the movable base and height of the upper surface of needle plate creates steps on the workpiece cloth which may cause the start point and the end point of the circular stitch to be incoincidental to result in a poor looking circular stitches. To address such concern, the movable plate is configured to be generally planar such that the thickness or height of the movable base and the pin are configured at relatively small dimensions with only the triangular shaped cloth slider protruding from the upper surface of the movable base so as not to prevent the rotation of the workpiece cloth.
Circular stitcher disclosed in JP 2008-253725 A makes adjustments in positioning of the movable base and consequently the needle by laterally moving the movable base depending on the size of the circular stitch to be sewn. However, because the circular stitcher inclusive of the movable base is generally planar in structure, the user or the operator may have a hard time in repositioning the movable base in the absence of a handle, for example, for user operation.